Connecting Optiplex GX620 to home wireless internet network

Hi!

I just recently got an Optiplex GX620, small form.  I would like to connect this computer to my home wireless network.  The GX 620 does have a Broadcom NetXtreme 57xxxGig Controller.  I am assuming I will need a wirelss adapter.   I have a Dynex Wireless G adapter card, but that won't fit in the PCI slot of the GX 620 small form.  Does anybody have any suggestions?  Should I go with a usb network adapter?  I've never used one and I'm crossing my fingers they work well in home networks.

Thanks!